Extension column lock



April 11, 1950 w. H. HORTON EXTENSION COLUMN LOCK Filed Sept. 25, 1947 WILLIAM H. HORTON INVENF'OR 8% A TTijRNEYS Patented Apr. 11, 1950 2,503,738 EXTENSION COLUMNFIJO'CK William Horton, Rochester,N-. 36., assignor =to Eastman Kodak Company, Rochester, .N. .Y., a eorporationof .NewJersey Application septeinber 25, 1947',Selial No. 773,041

The present invention relates to an extensible column or supporting member comprising a .pair of telescoping tubular members, and more particularly to a mechanism for looking or holding the im'embersin any position of adjustment.

The present invention has, therefore, :-as its principal object the provisionofalock for effectively retaining a pair of-extensible telescoping tubular members in any position .Of adjustment.

A further objectof the invention is the provision of a lock of the class described which will effectively retain the members in adjusted position, yet may be readily and easily released to permit the members to be moved relatively to another position of adjustment.

Still another object of the invention is ;a lock of thetype referred'to which is simple, rugged, easy to operate and positive and effective in its action.

To these and other ends, theinventiont-resides in certain improvements and combinations .of parts, all as will be hereinafter more/fully described, the novel features being pointed 'outiin the claims at the end of the specification.

-In-the drawings:

Fi'g. lis an exploded view of an exten'sible' col umn' and the locking mechanism therefor, showing the relation of the various parts; I

Fig. 2 is a view of the extensible column with the locking mechanism in position thereon; and

Fig. 3 is a vertical sectional view through the locking mechanism and taken substantially in line 33 of Fig. 2, showing the arrangementfor moving the actuating shoe into position to lock the telescoping members.

Similar reference numerals throughout the various views indicate the same parts.

Ajpair of tubular telescoping cylindrical'members II and I2 are adapted to cooperate to provide'an extensible column or supporting member, the member H being the outer member'an'd'the member 12 being the 'innermember. These members may be of any suitable length depending upon the purpose for which they are to be used. When the members are to be adjusted, the inner member is moved or slid a'xially relative to the outer member, as is apparent. However, when the parts are adjusted, it is necessary to lock or retain the members against accidental or inadvertent axial movement.

To secure this result, the present invention provides a novel and simple locking device which eflectively holds or locks the members against relative movement. However, when the adjustment of the members is to be changed, the look may be :readilyiand easilycreleaseu ito-iepermit'rthe: members to he slid :in telescopic relation until the :desired position is reached, whereupon the lock is again operated to clamp the positioned in the slots l6 and are s1ight1y sma1i'erthan the latter so that they may be moved'radially therein. Also, the shoes have "a thickness which is slightly greater than-the thickness 601" the wall of the member 1 L me-purpose 'of arrangement will be later described. The curved outer surface 20 of each shoe "is substantially concentric with 'the outersurfacefl o'fth-e outer member 'I I, while the inner surface 22 ofea'ch shoe is substantially concen ti'ic with the outer surface 23 of the inner'member l 2.

A retaining ring 2 overlies the shoes ll, 18

and 1-9 to retain the latter *the'Tsl'ots l li and between the inner surface -'2 5 "or ther'm'g and *ith'e it, as

outer surface 223 of the inner member best'shown'in" Fig. 3. The ring-2 is held-"imposition on the outer member =12 *by'm'ean's of "a S et' screw "26 which extends "through "an openin 2-! inthe ring andinto contact with the surface ill of'the outer member I lyas'is'apparent. Thus, thering 24 not only retainstheshoesin th -slot l6 but also 'cooperates'with the inner member I? "to r'etainthe shoes in wedg'ingor'locking rel'a tion with the inn'erm'ember"tolock the member's against relative "movement, as'willbe later described.

The shoes I1 and I8 are preferablyformedo f a suitable plastic 'mater'ia1 so as not to score or scratch the surface "23 "of "the innermem'b enthe disadvantage of which will'benbvious. 'TheJs'hOe ['9 1 is, however, "preferably :formed of 'metal. "The M ring "24 'is formed with a threaded opening i"2'8 adapted to receive an adjusting screw '29, the

end 30 or which is adapted'to engage the outer surface 29 of the shoe it as clearly indicated in Fig. 3.

In adjusting the length or the column or supporting member, the members II and 12 are slid axially relative to each other until the desired length has been secured. Then the adjusting nut 29 is screwed in to bring the end 30 into engagement with the shoe [9 to move the latter radially inwardly and into contact with the outer surface 23 of the inner member 12. Further movement of the screw 29 will then serve to shift the inner member 12 radially a slight distance to bring the outer surface 23 thereof into engagement with the inner surfaces 22 of the shoes I1 and I8 to wedge the latter between the outer surface 23 of the inner member l2 and the inner surface 25 of the retaining ring 24. Such wedging serves to clamp or lock the inner member frictionally to the outer member with sufiicient force to prevent inadvertent or accidentalrelative movement of the members. the retaining ring 24, the locking action can be broadly considered as being due to the wedging As the adjusting nut 29 is carried by of the shoes l1, l8, and 19 between the inner member I2 and retaining ring 24. When, however, the column length is to be changed, the nut 29 is backed off to release the clamping relation of the shoes to free the inner member. The latter may then be slid axially in the outer member to a new position of adjustment, whereupon the nut 29 is again screwed in to bring the shoes into clamping relation with the inner member to lock the members effectively against relative axial movement.

While one embodiment of the invention has been, disclosed, it is to be understood that the inventive idea may be carried out in a number of Ways. This application is, therefore, not to be limited to the precise details disclosed, but is intended to cover all variations and modifications thereof falling within the scope of the appended claims.

I claim:

1. In an extensible column, the combination of a pair of thin telescoping tubular members, the outer of said members being formed with a plurality of axially aligned and peripheral spaced I slots, locking shoes positioned loosely in said slots and adapted to engage the inner of said members to lock said members against relative movement, means for retaining said shoes in position in said slots, and a screw carried by said outer member for engaging one of said shoes only to move the latter into engagement with said inner member to shift the latter into locking relation with said shoes.

2. In an extensible column, the combination, of a pair of thin telescoping tubular members, the outer of said members being formed with a plurality of arcuate slots, locking shoes positioned loosel in said slots and adapted to engage the inner of said members to lock said members against relative movement, a ring carried by said outer member to retain said shoes in position in said slots, and a threaded member carried by said ring for moving one of said shoes only toward. said inner member to lock the latter against all of said shoes.

3. In an extensible column, the combination, of

a pair of telescoping tubular members, the outer of said members being formed with a plurality of axially aligned and peripheral spaced arcuate slots, arcuate locking shoes positioned loosely in said slots and having a thickness greater than said outer member and adapted to engage the inner member to lock said members against reia tive movement, a ring carried by said outer member and overlying said shoes to retain the latter in said slots, and a threaded member carried by said ring for engaging and moving one only of said shoes into engagement with said inner member to shift the latter to wedge the other shoes between said inner member and said ring so that said other shoes will cooperate with said one shoe to lock the inner member against movement relative to the outer member.

4. In an extensible column, the combination, of

' a pair of thin cylindrical telescoping tubular members, the outer of said members being formed with a plurality of axially aligned and peripherally spaced arcuate slots extending therethrough, ar-

cuate locking shoes loosely positioned in said slots and having a thickness greater than said outer member, a ring carried by said outer member and engaging the outer surfaces of said shoes to retain the latter in said slots, the inner surfaces of said shoes being substantially concentric with the outer surface of said inner member, and a radially movable screw carried by said ring for moving one of said shoes only radially into contact with said inner member to cause all of said shoes to wedge between said inner member and said ring to lock said inner member to said outer member.

5. In an extensible column, the combination, of a pair of thin cylindrical telescoping tubular members, the outer of said members being formed.

with a plurality of axially aligned and peripherally spaced arcuate openings extending therethrough, arcuate locking shoes loosely positioned in said openings and having a thickness greater than said outer member, a ring carried by said outer member and engaging the outer surfaces of said shoes to retain the latter in said openings,

the inner surfaces of said shoes bein substanti-,-

ally concentric with the outer surface of said inner member, a radially movable threaded membercarried by said ring for moving only one of said shoes radially into contact with said inner member to cause all of said shoes to wedge between said inner member and said ring to lock said members, and means for retaining said ring imposition on said outer member to overlie said shoes.

WILLIAM H. HORTON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 836,376 Fancher Nov. 20, 1906 1,295,412 Baines Feb. 25, 1919 1,394,596 Wohl et al Oct. 25, 1921 1,744,521 Briese et a1 Jan. 21, 1930 2,038,806 Sellar Apr. 28, 1936 2,189,644 Wingard Feb. 6, 1940 FOREIGN PATENTS Number Country Date 251,868 Germany Oct. 10, 1912 

